I have this theory. I am hoping the DGR community could prove or disprove it. The people who have been reading the overstable Roadrunners thread are now rolling their eyes

My theory is that the height of the parting line is an easy way to tell which disc will be more overstable.

Homework Assignment:Take 2 newish discs of the same mold and place them both on a flat surface so their noses are kissing. I say newish because the parting lines are much easier to see when they are newish. The higher the parting line the more overstable they are. Throw these discs and see if my theory is right. There is more visible variation between parting lines on the faster drivers so that might be the easiest thing to try this on.

So far it has worked for the few molds that I've tried it with. Tell me I'm right, tell me I'm wrong, or tell me to shutupanddropitalready!

Last edited by marmoset on Fri Nov 13, 2009 9:24 pm, edited 2 times in total.

Golf is a lot of walking, broken up by disappointment and bad arithmetic. ~Author Unknown

This is good news... I think this could be a valuable tool if you get the opportunity to fondle before you buy. It would have saved me some money for sure! I have a bunch of discs that turned out to be mutants and I was not happy with them...

Whoa. I have a freakishly overstable 12x teebird that I just compared to my other teebirds and its parting line is significantly higher than the rest. Your ideas are intriguing to me and I wish to subscribe to your newsletter.

This seems to be a consequence of wing height, which is why tuning discs work. The parting line should be in the same place wrt lip on identical molds. Therefore, the only way to get variation in parting line height would be through wing height differences which could result from the cooling process and/or storage pressures. When you tune one less stable you flex the top of the disc so that the wing is lower wrt the bottom edge, thus lowering the parting line. Visa versa for tuning more overstable. So, to me the parting line correlating to stability is a consequence/symptom of wing height variation and is not itself responsible for the effect.